This International Standard applies to the family of fibre optic filters. These components have
all of the following general features:
– they are passive for the reason that they contain no optoelectronic or other transducing
elements which can process the optical signal launched into the input port;
– they modify the spectral intensity distribution in order to select some wavelengths and
inhibit others;
– they are fixed, i.e. the modification of the spectral intensity distribution is fixed and can not
be tuned;
– they have input and output ports or a common port (having both functions of input and
output) for the transmission of optical power; the ports are optical fibre or optical fibre
connectors;
– they differ according to their characteristics. They can be divided into the following
categories:
? short-wave pass (only wavelengths lower than or equal to a specified value are
passed);
? long-wave pass (only wavelengths greater than or equal to a specified value are
passed);
? band-pass (only an optical window is allowed);
? notch (only an optical window is inhibited).
It is also possible to have a combination of the above categories.